<!doctype html>
<html>
	<head>
		<meta charset="utf-8" />
		<title>Leaflet debug page - GeoJSON</title>
		<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=0" />
		<link rel="stylesheet" href="../../dist/leaflet.css" />
		<link rel="stylesheet" href="../css/screen.css" />
		<style>
			.info {
				padding: 6px 8px;
				font: 14px/16px Arial, Helvetica, sans-serif;
				background: white;
				background: rgba(255,255,255,0.8);
				box-shadow: 0 0 15px rgba(0,0,0,0.2);
				border-radius: 5px;
			}
			.info h4 {
				margin: 0 0 5px;
				color: #777;
			}
	
			.legend {
				text-align: left;
				line-height: 18px;
				color: #555;
			}
			.legend i {
				width: 18px;
				height: 18px;
				float: left;
				margin-right: 8px;
				opacity: 0.7;
			}
		</style>
		<script type="importmap">
			{
				"imports": {
					"leaflet": "../../dist/leaflet-src.esm.js"
				}
			}
		</script>
	</head>
	<body>
		<div id="map"></div>
		<script type="module">
			import {Map, TileLayer, Control, DomUtil, GeoJSON} from 'leaflet';
			import statesData from './us-states.js';

			const map = new Map('map').setView([37.8, -96], 4);
			const tiles = new TileLayer('https://tile.openstreetmap.org/{z}/{x}/{y}.png');

			map.addLayer(tiles);

			// control that shows state info on hover
			const info = new Control();

			info.onAdd = function () {
				this._div = DomUtil.create('div', 'info');
				this.update();
				return this._div;
			};

			info.update = function (props) {
				this._div.innerHTML = `
					<h4>US Population Density</h4>
					${(props ? `<b>${props.name}</b><br />${props.density} people / mi<sup>2</sup>` : 'Hover over a state')}
				`;
			};

			map.addControl(info);

			// get color depending on population density value
			function getColor(d) {
				return (
					d > 1000 ? '#800026' :
					d > 500  ? '#BD0026' :
					d > 200  ? '#E31A1C' :
					d > 100  ? '#FC4E2A' :
					d > 50   ? '#FD8D3C' :
					d > 20   ? '#FEB24C' :
					d > 10   ? '#FED976' :
					'#FFEDA0'
				);
			}

			function style(feature) {
				return {
					weight: 2,
					opacity: 1,
					color: 'white',
					dashArray: '3',
					fillOpacity: 0.7,
					fillColor: getColor(feature.properties.density)
				};
			}

			function highlightFeature(e) {
				const layer = e.target;

				layer.setStyle({
					weight: 5,
					color: '#666',
					dashArray: '',
					fillOpacity: 0.7
				});

				layer.bringToFront();

				info.update(layer.feature.properties);
			}

			const geojson = new GeoJSON(statesData, {
				style,
				onEachFeature,
				attribution: 'Population data &copy; <a href="http://census.gov/">US Census Bureau</a>'
			});

			map.addLayer(geojson);

			function resetHighlight(e) {
				geojson.resetStyle(e.target);
				info.update();
			}

			function zoomToFeature(e) {
				map.fitBounds(e.target.getBounds());
			}

			function onEachFeature(feature, layer) {
				layer.on({
					mouseover: highlightFeature,
					mouseout: resetHighlight,
					click: zoomToFeature
				});
			}

			const legend = new Control({position: 'bottomright'});

			legend.onAdd = function () {
				const div = DomUtil.create('div', 'info legend');
				const grades = [0, 10, 20, 50, 100, 200, 500, 1000];
				const labels = [];

				for (let i = 0; i < grades.length; i++) {
					const from = grades[i];
					const to = grades[i + 1];

					labels.push(
						`<i style="background: ${getColor(from + 1)};"></i> ${from + (to ? ` &ndash; ${to}` : '+')}`
					);
				}

				div.innerHTML = labels.join('<br>');
				return div;
			};

			legend.addTo(map);
		</script>
	</body>
</html>
